CVE-2017-8658 in Chakra Core
Summary
by MITRE
A remote code execution vulnerability exists in the way that the Chakra JavaScript engine renders when handling objects in memory, aka "Scripting Engine Memory Corruption Vulnerability".
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Analysis
by VulDB Data Team • 01/08/2021
The vulnerability identified as CVE-2017-8658 represents a critical remote code execution flaw within Microsoft's Chakra JavaScript engine, which serves as the core rendering component for Internet Explorer and other Microsoft applications. This vulnerability specifically manifests during the handling of objects in memory, creating a memory corruption scenario that adversaries can exploit to execute arbitrary code remotely. The Chakra engine is responsible for interpreting and executing JavaScript code within Microsoft's web browser environment, making this flaw particularly dangerous as it affects the fundamental security boundaries of web applications.
The technical nature of this vulnerability stems from improper memory management within the Chakra JavaScript engine when processing certain object types and memory operations. When the engine encounters specific patterns of object manipulation in memory, it fails to properly validate or sanitize memory access operations, leading to memory corruption that can be leveraged by attackers. This memory corruption occurs during the rendering process of JavaScript objects, particularly when dealing with complex object hierarchies or when objects are manipulated in ways that exceed expected memory boundaries. The flaw operates at a low level within the JavaScript engine's memory management subsystem, making it particularly challenging to detect and prevent through traditional application-level security measures.
The operational impact of this vulnerability extends beyond simple browser exploitation, as it can be leveraged in various attack scenarios including drive-by downloads, malicious websites, and social engineering campaigns. Attackers can craft malicious web pages that, when loaded in Internet Explorer, trigger the vulnerable code path in Chakra, allowing them to execute arbitrary code with the privileges of the affected user. This remote code execution capability enables full system compromise, data exfiltration, and persistence mechanisms that can be used for advanced persistent threats. The vulnerability affects multiple Microsoft products including Internet Explorer versions 11 and earlier, as well as other applications that utilize the Chakra JavaScript engine for scripting functionality, creating a broad attack surface.
Microsoft addressed this vulnerability through security updates released in their August 2017 security bulletin, which included patches for the Chakra JavaScript engine memory handling routines. Organizations should prioritize immediate deployment of these patches to mitigate the risk of exploitation, as the vulnerability was actively exploited in the wild prior to the release of security updates. Security professionals should also implement network-based protections such as web application firewalls and browser hardening measures to reduce the attack surface. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be mapped to ATT&CK technique T1203, which covers exploitation for execution through browser vulnerabilities. Defense in depth strategies should include monitoring for suspicious JavaScript behavior, implementing strict browser security policies, and maintaining current threat intelligence feeds to identify potential exploitation attempts targeting this specific memory corruption vulnerability.